ya try bypassing it by applying direct power, its only a solenoid so maybe direct power from the battery (or a wire that only powers with the key)

 

I have never dealt with this solenoid. But being a solenoid I would think you should be able tp mechanically defeat or engage the solenoid using shims, set screw or a plug of some type. I would suggest leaving the computer out of it. It simply has to be some action that restricts oil flow to the lifters. Thinking out loud.. Good luck..